(2y-7)(8+y)=0

Solution for (2y-7)(8+y)=0 equation:

(2y-7)(8+y)=0

We add all the numbers together, and all the variables

(2y-7)(y+8)=0

We multiply parentheses ..

(+2y^2+16y-7y-56)=0

We get rid of parentheses

2y^2+16y-7y-56=0

We add all the numbers together, and all the variables

2y^2+9y-56=0

a = 2; b = 9; c = -56;
Δ = b2-4ac
Δ = 92-4·2·(-56)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-23}{2*2}=\frac{-32}{4}
=-8
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+23}{2*2}=\frac{14}{4}
=3+1/2
$